Lysosomes Overview, Types and Morphology

Types of Lysosomes
There are two main types. These include:

  • Primary lysosomes – are formed from Golgi apparatus appearing as small vesicles. Although primary lysosomes are popular on Golgi apparatus, they also occur as granulocytes and monocytes. These lysosomes are surrounded by a single phospholipid layer and contain acid hydrolases. The pH value of the acid in these vesicles is important in that its changes activate or deactivate the enzymes. Ultimately, most of the primary granules will fuse with phagosomes, which results in the formation of secondary lysosomes.
  • Secondary lysosomes – are formed when primary lysosomes fuse with phagosomes/pinosome (they are also referred to a endosomes). The fusion also causes the previously inactive enzymes to be activated and capable of digesting such biomolecules as nucleic acids and lipids among others.

Compared to primary lysosomes, secondary are larger in size and capable of releasing their content (enzymes) outside the cells where they degrade foreign material. A majority of lysosomal enzymes function inside the acidic environment, which is why they are referred to a acid hydrolases.